Heathrow Terminal Three

Project overview

Project name: Heathrow Terminal Three
Contractor: Mace
Sub contractor: Itech Roofworks
System: Firesmart Pyrobar Carrier Membrane and Sealoflex Solvent Free liquid applied waterproofing

Project description: Refurbishment of 6300m2 of roof at London Heathrow’s Terminal 3, Pier 6. Works were completed on both day and night shifts over an occupied airport.

As an international airport operating 24/7, Heathrow required that all works were carried out without any impact to passengers. This effected the choice of materials, organisation of personnel and the logistics of getting staff and materials on and off-site.


Itech Construction Director and BMI’s Technical Support team surveyed the roof and found that several sections showed signs of long-term water damage that required replacing. A working plan was devised that allowed the damaged sections of plywood to be replaced without interrupting the activities of the terminal.

The scale of the project meant setting up five teams, a total of 50 operatives, on both day and night shifts. The 24-hour operation consisted of the night shift stripping out the existing mechanically fixed single ply and installing Firesmart Pyrobar Carrier Membrane to the plywood substrate to create a weatherproof roof. The day shift then applied BMI Sealoflex Solvent Free Waterproofing Membrane if weather permitted or prefabricated the replacement sections.

The plant rooms proved the most complex part of this project as they provided limited access for the operatives. Working at night, around extensive pipework and ducting, operatives had to strip the existing single ply, replace plywood, build bunding and weather with the Sealoflex system all within the confined space. This required thorough planning, immense skill and attention to detail to install.

Health and safety

Both the main and the sub-contractors managed the health and safety risk by following the Four steps to safety guide, these are to observe, engage, improve and don’t walk by – empowering all site members to recognise and challenge the actions of others. Itech also installed and managed extraction ventilation, required to ensure dust particles and bituminous odours did not enter the airport ventilation systems during installation. Any breach could have set off the fire alarms, causing chaos to the airport.

New technologies

Heathrow Airport required that the new roof be installed without affecting its operations, this led BMI to develop the Pyrobar Carrier Layer incorporating Firesmart bitumen and BMI Sealoflex Solvent Free Coating with additional fire retardants.

Now one of the world’s busiest airport terminals is covered by a BMI 20 year guarantee and will not need anything but routine maintenance for decades.

If you would like more information about our flat roof guarantees please complete the form below.


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Heathrow Terminal Three